Adaptive Radiation Boost for Rectal Cancer

NCT07221058 | Recruiting Phase 1 DMC

• 2 other identifiers: RT-23125-1024
• Study Type: interventional
• Target: 37
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this clinical trial is to find out if giving extra adaptive radiation therapy after standard chemoradiation treatment is safe and helpful for people with rectal cancer. The main questions the study aims to answer are:

• Can this approach help target the most aggressive cancer cells more accurately, while protecting nearby healthy tissue?
• Can it reduce the side effects that people may experience during treatment? Participants will:
• First receive standard treatment: radiation (45 Gy in 25 sessions) along with a chemotherapy pill called capecitabine.
• Then get extra radiation using MRI scans every two weeks to adjust the treatment based on how the tumor responds.
• Use a small balloon during treatment to help aim the radiation and protect healthy areas.
• Finally, receive additional chemotherapy (such as FOLFOX) for four months.

Conditions

Rectum Cancer, Adenocarcinoma

Keywords

Adaptive Radiation Therapy; Rectum Cancer; Adenocarcinoma; Organ Preservation; Total Mesorectal Excision

Outcome Measures

Primary Outcomes (2)

• MTD will be evaluated by monitoring the rate of dose limiting toxicities (DLTs) defined as acute Grade 2+ gastrointestinal toxicity probably or definitely related to radiation.

  From the initiation of rectal adaptive radiotherapy boost to 90 days after the last dose of boost, for a total of ~ 120 days.

• Feasibility of a rectal boost that targets at least 90% of the rectal planning tumor volume with the 80% prescribed dose while limiting the outer 3 mm of the rectal wall to no more than 50% of the prescription dose delivered to 0.1cc.

  Feasibility will be determined based on successful implementation and completion of standard chemoradiotherapy followed by experimental rectal adaptive radiotherapy boost utilizing CT-MR fusion that targets at least 90% of the rectal PTV\_Eval with the 80% prescribed dose while limiting the outer 3 mm of the rectal wall to no more than 50% of the prescription dose delivered to 0.1cc in ≥ 70% of ART fractions for the patient population enrolled in the study. This will be assessed at the MTD.

  From the ART boost initiation to the end of the ART boost, for a period of ~ 5 weeks

Secondary Outcomes (4)

• Estimate the efficacy of bi-weekly adaptive radiotherapy boost fractions by complete response rate, near complete response rate, and incomplete response rate as per Memorial Sloan Kettering Cancer Center (MSKCC) criteria.

  From the end of rectal adaptive radiotherapy boost to the end of study, for a total of ~ 5 years.

• Estimate total mesorectal excision (TME) free survival following treatment with the study regimen.

  From the end of treatment to the end of the study, for a total of up to 5 years.

• Estimate overall survival (OS) following treatment with the study regimen.

  From the end of treatment to the end of study, for a total of up to 5 years.

• Estimate early and late toxicity following treatment with the study regimen.

  From the initiation of rectal radiation boost treatment to the end of the study, for a total of ~ 5 years.

Study Arms (1)

Adaptive Radiotherapy Boost Following Standard Pelvic Chemoradiation

EXPERIMENTAL

Adaptive Radiotherapy

Radiation: Adaptive Radiotherapy Boost

Interventions

Adaptive Radiotherapy Boost RADIATION

Patients will receive one boost fraction every two weeks, targeting the primary tumor within the rectum plus a 2 mm Planning Target Volume (PTV) margin. Any regional lymph nodes that measure at least 5 mm in short axis on the day of treatment will receive treatment with the ART dose being given to the primary rectal tumor.

Adaptive Radiotherapy Boost Following Standard Pelvic Chemoradiation

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Subjects must have histologically or cytologically confirmed rectal adenocarcinoma.
• Subjects must have T2-3, N0-1, M0 rectal cancer. Staging will be done by MRI pelvis and CT chest and abdomen with contrast. PET-CT will be an acceptable alternative for the CT chest and abdomen.
• Subjects must be willing to undergo MRI scans.
• Age ≥18 years.
• ECOG performance status 0 or 1.
• Estimated survival of ≥ 12 months.
• Subjects must have normal organ and marrow function as defined below
• Absolute neutrophil count \> =1,000/mcL
• Platelets \>= 75,000/mcL
• Total bilirubin \< 3 mg/dL
• Subjects must be able to tolerate the chemotherapy regimens outlined in the treatment plan (Section 5.0), both before and after ART.
• Before ART: Capecitabine at a dose of 825 mg/m²
• After ART: FOLFOX combination chemotherapy, or 5-FU, or capecitabine

You may not qualify if:

• Subjects who have been previously treated for rectal cancer are excluded.
• Subjects with rectal cancer involving the anal canal are excluded. (Rectal cancer abutting the anal canal will be allowed.)
• Subjects must not be receiving any other investigational agents.
• Subjects may not have had prior pelvic radiation.
• Subjects should not have had a cancer actively treated within the last 3 years, excluding non-melanoma skin cancer.
• Subjects must not have uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements.
• Any condition or significant co-morbidity that prevents safe delivery of ART per the discretion of the treating physician(s).
• Subjects must not be pregnant or breast-feeding.

Sponsors & Collaborators

• Fox Chase Cancer Center: lead
• Varian Medical Systems: collaborator

Study Sites (1)

Fox Chase Cancer Center

Philadelphia, Pennsylvania, 19111, United States

RECRUITING

MeSH Terms

Conditions

Rectal Neoplasms; Adenocarcinoma

Condition Hierarchy (Ancestors)

Colorectal Neoplasms; Intestinal Neoplasms; Gastrointestinal Neoplasms; Digestive System Neoplasms; Neoplasms by Site; Neoplasms; Digestive System Diseases; Gastrointestinal Diseases; Intestinal Diseases; Rectal Diseases; Carcinoma; Neoplasms, Glandular and Epithelial; Neoplasms by Histologic Type

Study Officials

• Joshua Meyer

  Fox Chase Cancer Center

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Joshua Meyer, MD

CONTACT

215-728-2667; Joshua.Meyer@fccc.edu

Jianli Hu, MD, PhD

CONTACT

267-449-1431; Jianli.Hu@fccc.edu

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: October 22, 2025
• First Posted: October 27, 2025
• Study Start: October 24, 2025
• Primary Completion (Estimated): November 1, 2028
• Study Completion (Estimated): November 1, 2029
• Last Updated: December 9, 2025

Record last verified: 2025-12

Locations

US (1)